The Bald Eagle (Accipitriformes: Accipitridae: Haliaeetus leucocephalus) has been an iconic symbol throughout United States history. Long sacred to several Native American cultures, it was adopted as the national bird of the United States in 1782. Since then it has appeared on most official US government seals and is widely regarded as the symbol of America. In spite of its prominence as a national icon and its importance to Americans, however, we nearly drove this species to extinction in the twentieth century.
It’s estimated that several hundred thousand Bald Eagles inhabited the United States throughout the nineteenth century. By the twentieth century hunting, trapping, and poisoning of these birds became relatively common practices. People once mistakenly believed that Bald Eagles attacked livestock and left no fish for anglers, and treated the birds as pests that needed to be eradicated.
The threat to these eagles and many other birds of prey intensified with the widespread use of potent pesticides like DDT. These toxic compounds accumulated in water, found their way into fish, and then into the birds that ate them. This resulted in malformed eggs with thin shells, leading to a rapid increase in chick mortality. By the 1950s there were fewer than 500 nesting pairs of Bald Eagles remaining in the lower 48 states.
Increased awareness of the harmful ecological effects of DDT lead to public pressure that resulted in a ban on its use in 1972. Since then Bald Eagles have been recovering, and today it’s estimated that there are about 70,000 individuals across the continent.
You can find these large, majestic birds throughout most of North America, but their range varies with the seasons. They overwinter mostly in the lower 48 states and northern Mexico, and breed in the summer across most of Canada, Alaska, and the east coast. In some parts of the northwest they can be found year-round. They’re often seen near rivers, lakes, and other shores where fish are common. Although they feed predominantly on fish, they will also prey upon smaller birds and mammals.
In their breeding range males and females work together to construct enormous and conspicuous nests of sticks in trees. Some of these can reach eight feet across (2.4 m) and weigh up to one ton (907 kg). Nesting pairs raise one to three young per year, and in the absence of human interference have been increasing their population and range. Although placed on the federal endangered species list in 1967, conservation successes lead to their removal in 2007.